Santos and FARC leader Timoleon "Timochenko" Jimenez presided over a ceremony where the government and rebel leaders signed a deal on justice for crimes committed during the conflict, which had been the key issue blocking progress in the negotiations.

Santos made a surprise trip to Havana, where the talks have been taking place, for the signing ceremony -- the first time he has appeared at the negotiations he set in motion and has staked his presidency on successfully concluding.